提出了一种考虑人眼视觉系统特点的不树分割编码算法，在分析视觉系统对比度特性的基础上，首先提出了一个基于视觉敏感的四叉树分割标准。

In this paper, a segmentation-based hybrid image coding algorithm is proposed which takes the features of the human vision system (HVS) into account. First, a novel criterion for quadtree-based segmentation using contrast masking is presented. This segmentation criterion performs better than the frequently used criterion, block variance. With this criterion, the original image is segmented into uniform blocks of 32×32, 16×16 and blocks of 8×8 to be classified. Then a two-level classifier, based on contrast masking sensitivity and polynomial approximation error, is further applied to the blocks of 8×8 such that all blocks are classified into a few categories: uniform blocks of different sizes, smooth blocks of 8×8 and non-smooth blocks of 8×8. At last, block mean, polynomial approximation and DCT coding are applied to the blocks accordingly. The experimental results demonstrate that the proposed algorithm performs much better than JPEG.